HP CIFS Server 3.0d Administrator's Guide version A.02.02 (Edition 5)

HP CIFS Deployment Models
Samba Domain Model
Chapter 9 199
the password server parameter to the names of the PDC and may also
add the names of one or more BDCs. Set the domain master parameter
to no to let the PDC take control.
As with the PDC and BDC, you set the passdb backend parameter to
the name of LDAP server to centralize POSIX and Windows account
database management. Using LDAP requires to install the HP
LDAP-UX Integration software and configures the LDAP client to
consolidate POSIX and Windows users on the LDAP directory.